Process of and device for drawing bellied objects of sheet metal



' Apr. 17, 1923. 1,4513% C. NEUBAUER PROCESS OF AND DEVICE FOR DRAWING BELLIED OBJECTS OF SHEET METAL Filed Sept. 1'7, 1921 2 Sheets-$heet 1 Apr. 17, 1923.

I C. NEUBAUER PROCESS OF AND DEVICE FOR DRAWING BELLIED OBJECTS OF SHEET METAL Filed Sept. 17 1921 2 Sheets-Sheet 2 I shape.

Patented Apr. 17, 1923.

UNITED sra'rss PATENT @FFHCE.

CURT NE UBAUER, OF IVTECKLENBURG, GERMANY.

PROCESS OF AND DEVICE FOR DRAWING BELLIED OBJECTS OF SHEET METAL.

Application filed September 17, 1921.

To all whom it may concern:

Be it known that I, Cum" NEUBAUER, mechanical engineer, a citizen of the German Republic, residing at Sliiterufer 3, Schwe'rin i. Mecklenburg,Germany, have invented certain new and useful Improvements in or Relating to a Process of and Device for Drawing Bellied Objects of Sheet Metal, of which the following is a specification.

My invention relates to a process of and a device for drawing bellied objects of sheet metal. Bellied objects of sheet metal have heretofore been pressed or drawn in presses by means of positive and negative tools or made by the so-called rolling process. The process mentioned in the first place is admissible for certain dimensions only of the sheet objects. For large parts the pressure increases into such a degree that the process ceases to be economical and the necessary pressing moulds are impossible to makeon account of technical reasons. The rolling process which consists in the sheet being pressed into a hollow mould by means of a regularly shaped spherical or rounded pressing roll is applicable only when the transitions in the hollow shape are gradual, while deep excavations require numerous operations so that the process becomes expensive in time and cost.

The present invention avoids the draw I ing counter-mould of the shape intended.

According to this process the countermould bears the outer shape of the object to be manufactured, while the developed surface of the drawing tool shows its inner In certain cases the developed sur- 1 face of the drawing tool or of the countermould may be interrupted by gaps or hollows. I f

This process is suitable for unskilled hands a and affords the advantage of the pressure required being moderate so that asa rule a single operation will be sufficient; may two or even more operations will be required. The new process will allow the moulding of 1 large sheets.

With powerful drawing machines the process is. also suitable for thick-plates and strips. The tools required aremuch cheaper than the press moulds because they are of simpler. 'constructionf-and in most cases are sufficiently strong when made of-hard wood;

Serial No. 501,417.

The drawing represents three instances of execution, namely Fig. 1 is a section through the tools required for making the shell of a boat accord ing to the present invention,

Fig. 2 is a cross section through Fig. 1 and phows the cross section of the boat in dotted mes;

Fig. 3 is a side view of a device for making the rear wall of a motorcar body.

gig. 4 is a cross section through Fig. 3 an Fig. 5 is the counter-mould for making an object of sheet metal with double curvature.

A slightly modified form of construction is illustrated in Figs. 6 and 7'in which a rotary counter-mould instead of a reciprocating one is provided, Fig. 6 being a transverse section and Fig. 7 a longitudinal section.

In the arrangement according to Figs. 1 and 2 the sheet is drawn between a developing tool and a fiat counter-mould, the latter making a progressive forward movement relatively to the axis of the drawing tool or vice versa. The circumference of the drawing tool is an exact evolution of the inner shape of the object to ;be formed. The evolution may be completed either with a full or a partial revolution of the tool. The length of the counter-mould into which the sheet is pressed while 'the tool is operated and the surface of which exactly corresponds to the outer shape of the object to be manufacturedmust therefore equal the length of the evolution of the tool. In most cases the sheet worked need not necessarily contact both tools; only the convex surface must be in full contact with the sheet while the concave surface may be provided with hollows into which theconvex part presses the sheet, so that the concave surface may differ from the exact shape of the object to be made. The'edges of the sheet are secured either in full length or partially by means of corresponding fixing devices.

In the arrangement according to Figs. 1

ment,-ar'e fixed to the machine frame; The:

counter-mould 6 may have a surface exactly corresponding to theouter shape of the;,ob-.

ject to be manufactured or, as the figure shows, may consist of a body provided wlth a hollow space 7' between the surfaces ,whereupon the sheet is fixed so'that the convex part of the drawing toolmay freely enter. The frame 9 serves to keep down the sheet 71, upon the fixing surfaces of thecounter-..

' mould.

Before the drawing operation the sheet it assumes the straight position marked in Fig. 2 by dotted lines. The frame 9 presses the sheet upon the fixing surfaces of the mould e the pressure being limited to an amount which I enables the sheet to be gradually pulled-out under the fixing frame 9 while i being worked without being bulged or plaitedl As soon as the counter-mould c with the sheet 72 fixed to it is moved forward under the drawing tool a mounted in fixed bearings the tool turns around its axle The toolsurface b othen acts on the sheet h and 'pressesthe same into the countermoul df c; the sheet beingat thesame time pulled out to a certain extent under the frame 9.. The borders which are left outside of the shaped portion are trimmed olf after the sheet has been taken out ofthecountermould] Forvery deep forms the height of the drawing tool a can be adjustable in order to perform the process in several consecutive.

operations. In Fig; 2 the other half completing the) shell of the boat is likewise shown in dotted lines.

' It results from the. description of thexnew process that the work need not necessarily.

inudotted lines In 'this :casethe counters.

mould i is convex and thedrawingtoolconcave. the counter-mould therefore representing, the'shape of thework in an uninterrupts. ed surface, .while the drawing. tool consists. of two parts Z and. m with thezdevelpping.

surfaces are and-pq respectiyely; The sheet .y'nis lto be insertedin a'l shapeu er e dicularly. bent with respect. to .the axis, of

i the drawingtool (Fig. and. ina position shown by dottedlines in Fig; 4. The -.,ref

erence letter J17 indicates the 'fixingbeams or fixingframeintendeditoliolddown the-sheet at fibot'h'li'edges in analogy- ..wit.l 1 ;the, fixing frame in :Figs.,.1 and 2, ;viz.: .in order -.to avoid ahulggingandiplaiting of the sheet.

a lengthwise clirection,,both tools] and m are operated, thus partly extracting the sheet from under the fixing beams and pressing it into the sharpedges at both sides. In

this way the sheet is also drawn over the convex part .inthe middle of the;sect ion and fitted to its shape even if the space between both parts Z and .mremains hollow.

The manufacture of an object the concavity of which is interrupted by a ridge (as per Fig. 5) is enabled by a counter support 9 in the" corresponding place of the mould. The evolution of shapes of this class is to be confined to the drawing tool as in the other cases referred to. a

The relative movement between. drawingtool and counter-moulcl:can be determined at will e. g. the latter may be fixed and the first may travel inasmuch as the axle is moved in a horizontal direction.

The dependence of the rotation of the; drawing tool upon the travel of the counter.

mould or vice versa' to the'end of producing a correct evolution of the parts upon each other may be secured either by friction .or by means of suitable gearing such as. cogwheels. and racks worm 'wheelsu screw spindles etc.. which preventa displacement not intendedavhile the evolution. is being performed.

Concerning now. the form of vconstruc-.

tion illustrated in Figsfi and 7, this is distinguished from that shown ,in Figs; 1-5 by the feature that instead of the reciprocating counter-mould i a rotary one is employed.

In all other respects, the combination and.

arrangement of theiparts maybe the same as already described The upper toola/ is attached to the rotatable shaft cl, and the counter-mould s is secured to a shaft 25 which is rotated with the same speed and in the same manner as the shaft (Z'. Thestationary bed 17-of the machine supports then solely the reciprocating: clamping. device, 34 into:

which the piece of sheet-metal 35: to be worked isplaced. .The clampingvdevice 34 may be driven. in :any desired manner, for instance by a cog-wheel 36 which meshes with a laterally arranged rack 37.

For;the; tools as well as for the countermoulds anysuitablen iaterial .mayibe usech In certain cases hard wood is suff cient, but.

steel, oast iron, etc, mayalso be applied.

. hat, ,1 claim isr v 1. A process for drawing, bellied sheet 7 metal articles, consecutive sections of whiCh,-, in the, drawing ,direction,, differ. in shape from. one, another, 7 comprisingjr he steps of drawing a metal sheet between a rotary.

drawingtool and asynchronously-moved coacting counter-mould,- while impartingto the sheet a progressive forward bodily movement .in the direction of its length ,and rel: 9131376 .to ithe axis of "the .drawingtool, .soi as weave.

the sheet from end to end thereof, and maintaining the distance between the tool axis and the plane of the mould constant during the entire movement of the sheet; substantially as described.

2. A' process for drawing bellied sheet metal articles, consecutive sections of which, in the drawing direction, differ in shape from one another, comprising the steps of positioning a metal sheet upon a countermould, drawing the sheet between the tool and mould while imparting to the mould a progressive forward bodily movement in the direction of its length and relative to the tool axis so as to cause the tool to act progressively upon the sheet from end to end thereof, and maintaining the distance between the tool axis and the plane of the mould constant during the entire movement of the mould; substantially as described.

3. Apparatus for drawing bellied sheet metal articles, consecutive sections of which, in the drawing direction, differ in shape from one another, comprising a rotary drawing tool, a counter-mould coacting with the drawing tool and movable synchronously therewith, and means for moving the metal sheet to be drawn between and synchronously with the said coacting elements and progressively forward bodily in the direction of its length without varying the distance between the tool axis and the plane of the mould, so as to cause the drawingtool to act progressively upon the sheet from end to end thereof; substantially as described.

4. Apparatus for drawing bellied sheet metal articles, consecutive sections of which, in the drawing direction, differ in shape from one another, comprising a rotary drawing tool having a circumferential working surface which is a progressive evolution of the successive portions of the inner surface of the article to be drawn, a counter-mould coacting with thedrawing tool and movable synchronously therewith and having aworking surface which corresponds in shape to the outer surface of said article and in length to the length of said tool surface, and means for moving the metal sheet to be drawn between and synchronously with the said coacting elements and progressively forward bodily in the direction of its length without varying the distance between the tool axis and the plane of the mould, so as to cause the drawing tool to act progressively upon the sheet from end to end thereof; substantially as described.

5. Apparatus for drawing bellied sheet metal articles. consecutive sections of which, in the drawing direction, differ in shape from one another, comprising a rotary drawing tool, a counter-mould on which the metal sheet to be worked is adapted to be positioned coacting with the drawing tool, and means for imparting to the mould and the sheet thereon synchronously with the rotation of the tool a progressive forward bodily movement in the direction of its length and relatively to the tool axis without varying the distance between the tool axis and the plane of the mould, so as to cause the drawing tool to act progressivelv upon the sheet from end to end thereof; substantially as described.

6. Apparatus for drawing bellied sheet metal articles, consecutive sections of which, in the drawing direction, differ in shape from one another, comprising a rotary drawing tool, a counter-mould von which the metal sheet to be worked is adapted to be positioned coacting with the drawing tool, means for clamping the sheet in place on the mould, and means for imparting to the mould and the sheet thereon synchronously with the rotation of the tool a progressive forward bodily movement in the direction of its length and relatively to the tool axis without varying the distance between the tool axis and the plane of the mould, so as to cause the drawing tool to act progressively upon the sheet from end to end thereof; substantially as described.

In testimony whereof I have affixed my signature.

CURT NEUBAUER. 

